Preservation of perfumes



aientccl July 13, 1943 2,324,341 PRESERVATION or renames Carl N. Andersen, WellcslcyrMasm, sealant to Lever Brothers Company, a corporation of Maine No Drawing. Application July 9. 1942,

. 1 Serial No. 450.293

'2 Claims.

This invention relates to a method of preventing or greatly inhibiting the development of undesirable odors and colors in perfume; the invention relates also to the resulting compositions.

it is an object of my invention to treat perfumes in order to arrest the deterioration of the fragrance and the development of undesirable odors, as well as to arrest the darkening in color that normally occurs upon exposure of perfume to air.

In accordance with my invention, I achieve the above objects by adding to the perfume a small quantity of an ascorbic acidor a similar compound of the type hereinafter described. These compounds, I believe, function primarily as antioxidants, thus preventing or arresting the oxidation' that would otherwise take place and cause the formation of undesirable odors and colors.

Most perfumes consist of a mixture of chemical compounds. As a rule, each of these chemical compounds by itself has a rather harsh odor. The delightful aroma, characteristic of flowers, is usually developed only when a number of chemical compounds are present in the proper combination and in the proper proportion, as they exist in nature, or as the skill of the chemist can combine them.

it is known that many of the compounds that are comprised in perfume are unsaturated or contain chemical groups that render them easily capable of oxidation. Geranium bourbon, ionine, heliotropine, aubepine, buxine, and' limonene or natural lemon and orange oils are but a few of many examples that could be named. The proddots of oxidation are compounds such as peroxides, ozonides, aldehydes and acids. The oxidation products in some cases are odorless and in many cases they possess undesirable odors. As the result of oxidation of perfume some of the compounds are decomposed togive odorless or unpleasant smelling compounds the delicate balance of the compounds in the perfume is destroyed, and the fragrance is materially altered. This can be readily demonstrated by exposing a sample of perfume to light and air and then comparing the exposed sample with an original sealed sample. In some instances the initial exposure to air results in a sweeter odor, due probably to the formation of terpenes, but this condition is only temporary and is followed by the development of rancidity.

The oxidation products of perfume are often daris colored and upon standing exposed to air, a perfume will darken in color. For example, a synthetic perfume prepared from'avariety of be added to perfume to prevent or materially reduce the loss of fragrance and the development of undesirable odors, along with a reduction in the darkening of the color. In some instances the addition of the ascorbic acid not only results in an inhibition in color change but produces a slight bleaching of the perfume, unattended by any undesirable change in odor.

Ascorbic acid is a substance naturally occurring in vegetable materials and also occurs in Various parts of the human anatomy; in fact, it contributes to normal metabolism and body health. In employing ascorbic acid as an antioxidant, therefore, I not only obtain advantages from the inhibition of undesirable color and odor formation, but in addition the material so treated is not rendered harmful because there is no inclusion of any substance that is in the least injurious to human tissue. The compounds similar to ascorbic acid are likewise unharmful.

I am not aware that it has heretofore been proposed to include an antioxidant in perfume. I amof the opinion that most substances heretofore suggested as antioxidants for use in other materials would probably be regarded as unsuitable for inclusion in perfume because of the delicate nature of the aroma and the possibility of the antioxidant reacting or otherwise modifying one or more of the constituents of the perfume, thereby altering the delicate balance of the ingredients and modifying the odor. I have discovered, however, that in addition to the advantage heretofore noted, no deleterious action can be attributed to the inclusion of ascorbic acid in perfume.

Ascorbic acid is more completely identified as.

B(or 3) keto l-gulono gamma lactone. This compound is composed of carbon, hydrogen and oxygen and contains hydroxyl and carbonyl groups, depending on whether or not it exists in the tautomeric enol or keto" form. Ascorbic to crystalline substance having the a and has a melting point of either source may be used in practicing the invention.

In practicing my invention, one-half gram of ascorbic acid may be added to 50 grams of perfume. Much smaller quantities, however, may be employed and the percentage may be as low as 1%. While larger quantities may be used, no particular advantage appears to accrue therefrom.

Amounts greater than that mentioned above may be employed but in seneral any improved results obtained by using a larger quantity are not economic. Much smaller amounts may be used and proportions as low as 1:25,000 and l:500,000 give noticeably improved results.

As additional illustrations of the invention, -1 may employ iso-ascorbic acid, reductic acid, and other compounds mentioned hereinafter in a manner and in an amount similar to that described previously. Tests show these compounds to be particularly effective in inhibiting the formation of undesirable odors and colors in perfume.

I have previously referred to compounds similar to ascorbic acid as included in my invention. In amplifying the meaning of this expression it should be noted that ascorbic acid exists in two forms, the 1" and the "d" form. The l-ascorbic acid also exists in two tautomeric forms, namely, the keto" and "enol" forms, which have the following formulae, respectively:

The other form of ascorbic acid, namely, the d-ascorbic acid, has the following formula:

g-OH Li men Thi also exists in similar tautomeric forms.

Ascorbic acid contains the "ene-diol" group, namely:

o-on

Lon

The ene-diol group can also exist in the tautomeric keto form:

The ene-diol group in ascorbic acid is also linked to the carbonyl group, which linkage has the following enol and keto forms:

My experiments with a variety of diflerent compounds having different but related structure lead me to believe that any compound containing the ene-diol group will have an antioxidant eflect in soaps and perfumes and mixtures there- 5 of similar to that of ascorbic acid. including those compounds in which the ene-diol group is linked to a carbonyl group, as above described, and also in which the ene-diol group is associated with a lactone group having the following general structure:

(E-OH E-DH a l The last mentioned ene-diol lactone group can exist in tautomeric forms, namely, the keto form or the enol form, respectively:

o o l i 1min fi-on =0 -on I H4l- 11%: A number of compounds which contain the ene-diol group show a chemical similarity to ascorbic acid, and I have found them to possess antioxidant properties in different degrees but always to a pronounced extent. Examples of these compounds are: reductic acid,

KsC-C=O --on H: &-OH hydroxy-tetronic acid. 0:0

' 3-01: ml and dihydroxy maleic acid.

nooc-c-on nooc- ---on Other compounds. and their empirical formulae, containing the ene-diol lactone group are: d-erythro-ascorbic acid,

5 dand l-arabo-ascorbic acid.

H-CHsOH 5 dand l-gluco-ascorbic acid, di-galacto-ascorbic acid, and l-gulo-ascorbic acid,

l-rhamno-ascorbic acid, and l-fuco-ascorbic 66 acid,

It will be understood that all these compounds, may exist in both diand 140m and in tautomeric keto and enol forms. Reference to a compound containing an ene-diol group, therefore, is intended to include any tautomers and optical isomers.

My invention is applicable to various antioxidant materials of the type herein generally disclosed and may be employed in a variety of products as described. The invention is understood to include all such modifications without departing from the spirit of the invention as defined in the appended claims.

Thi application is a continuation-impart of my application Serial Number 210,779, filed May 28, 1938.

Iclaim:

l. A perfume composition comprising essentially perfume and a relatively small amount of a substantially pure crystalline ascorbic acid added thereto for inhibiting undesirable changes in odor and loss of fragrance in the perfume.

2. A perfume composition comprising essentially perfume and a relatively small amount of a substantially pure solid compound added thereto for inhibiting undesirable ch n es in odor and loss of fragrance in perfume, said compoimd being selected i'rom the group consisting 01' allphatic and alicyclic compounds composed 01' car-- bon, hydrogen and oxygen and containing an ene-diol group.

CARL N. ANDERSEN. 

